The present invention relates generally to the field of electrical connectors and more particularly to mating electrical connectors and electrical plugs which may be advantageously employed in environments subject to electromagnetic radiation. For many years, electrical connectors have been built with metal shells and spring fingers and interference fits between shells have been used along with shielded cable to protect electrical circuits within the connectors from extraneous electromagnetic radiation (EMR) when the plug and receptacle of the connector set are mated. Protection of electrical circuits from stray EMR when the connector set is unmated has posed a problem in the past for which no adequate solution has been proposed. This condition is especially critical to electronic equipment in close proximity to radar or other transmitting equipment. Several methods have been used to provide this EMR protection to unmated connectors.
For instance, one such prior art connector includes a metal mask enclosing the insulator and socket contacts of the unmated connector receptacle with holes in the face of the mask to provide ingress of the plug pin contacts when mated. This receptacle design is based on waveguide technology where it is dependent on the length and diameter of the holes in the face of the electromagnetic protection masks to attenuate the extraneous signals. Such devices are generally only effective for large length-to-diameter ratios and becomes less effective at higher frequencies.
Another device that has been used in the past to protect against unwanted EMR utilizes mechanical doors that close over the face of the connector receptacle providing a metallic grounded shield around the electrical contacts. Such devices require considerable space for the doors and operating mechanism. Further, in these types of devices, it is very critical that good low resistance contact between the shell and doors is provided.